This is at idle, with a bit of foot on the pedal the noise is pretty clear.
https://flic.kr/p/EysDKi
https://flic.kr/p/EysDKi
This Noise
- Thread starter RBBailey
- Start date
Contractor
Active member
I guess I'd start with adjusting the valve clearances. It's a pretty quick job and is easy enough to rule something out.
BarryO
Well-known member
It's been amazing how much I can get done since retiring.
'lots of projects at the new place.I agree; check the valve clearance first
Viton will tell you that you may have a cap loose or missing causing this. You will soon find out after you remove the valve cover.
....LOL! Not on my timescale. That's probably a 3 hour job for me. Have only done it twice, so I have to relearn it every time. I did it on this last summer, but I did not have new caps, just basically did a check to make sure there was nothing amiss.
I'll see if I can get it done this evening. But I have a whole lot of trees I'm supposed to be cutting down today.
DefendersNW
Well-known member
No new caps needed unless you had misadjusted valves that caused wear or allowed one to escape...
Valve check on the Tdi needs to be done dead cold every third oil change (the 9k mile big service)
Napalm00
Technical Excellence Contributor
I'd loosen the rocker arms until you can remove the cap with a magnet. Check for flatness , if they are mushroomed, have scratches or have flaking chrome the need to be replaced . Slip your finger under the rocker arm ,it should be perfectly smooth.
If the caps are boned ,replace them with lr caps or the cheap vw equivalents.
If the caps are boned ,replace them with lr caps or the cheap vw equivalents.
I have a set of the VWs ready. I'll see about doing this tonight if I can stay awake now! But I need to let the truck cool down before I do it anyway.
Thanks,
Are there other things I should consider with a knock like this? When I took that video, the PSI was at about 20, water temp was 185, right after a drive. I don't hear it right now, but the engine isn't full warm.
Thanks,
Are there other things I should consider with a knock like this? When I took that video, the PSI was at about 20, water temp was 185, right after a drive. I don't hear it right now, but the engine isn't full warm.
I'm going to check the timing with a pin. And I'm going to pull the cover off and see what there is to see.
Assuming this is not the problem. There are a few other things I've notice about the way the truck runs: If I happen to be laying on the pedal looking to roll some coal, I can see some smoke from the tailpipe, just as I should. However, it seems to be kind of an inconsistent stream. (This isn't really the way I drive, but I like to test things to see when the smoke starts, etc...) Also, when going up a hill today, I might have heard a bit of a knock on top of all the other noise.
It seems to be running fine. But I've always been a little suspicious of it being out of norm. I need to drive a few other 300Tdi's to compare it to. And I know a friend of mine in a truck that was almost exactly 2000lbs heavier than mine was keeping up with me over the mountain, and he said he wasn't trying. He also got more than 4 mpg better than I did on the same trip. Other than the weight, he had a roof tent on, and larger tires.
Assuming this is not the problem. There are a few other things I've notice about the way the truck runs: If I happen to be laying on the pedal looking to roll some coal, I can see some smoke from the tailpipe, just as I should. However, it seems to be kind of an inconsistent stream. (This isn't really the way I drive, but I like to test things to see when the smoke starts, etc...) Also, when going up a hill today, I might have heard a bit of a knock on top of all the other noise.
It seems to be running fine. But I've always been a little suspicious of it being out of norm. I need to drive a few other 300Tdi's to compare it to. And I know a friend of mine in a truck that was almost exactly 2000lbs heavier than mine was keeping up with me over the mountain, and he said he wasn't trying. He also got more than 4 mpg better than I did on the same trip. Other than the weight, he had a roof tent on, and larger tires.
Napalm00
Technical Excellence Contributor
Checking your timing with a pin is great but it doesn't give you any real indication of the if the timing is accurate or not. Being able to move the pump half a millimeter in either direction can constitute it being retarded or advanced. I'd suggest getting a diesel timing kit with a gauge and checking it from there.
Since the pin has no real reference to if it's correct or not since the timing belt can be stretched or offer tooth or maybe just worn. So the pain would make it correct relative to a bad belt or incorrect starting information.
On a 200tdi you will have to remove the oil filter housing to be able to time it. The gauge and timing pin kit cost less than $100.
There are some great videos on how to Time-It. The target lift is 1.54 MM at top dead center and 1.6 mm for slightly more power. So as you can see less than a tenth of a millimeter of lift at top dead center can mean the difference between spot on an advanced
Too far advanced would cause a knocking sound the same to the pre detonation knocking sound that you have
Since the pin has no real reference to if it's correct or not since the timing belt can be stretched or offer tooth or maybe just worn. So the pain would make it correct relative to a bad belt or incorrect starting information.
On a 200tdi you will have to remove the oil filter housing to be able to time it. The gauge and timing pin kit cost less than $100.
There are some great videos on how to Time-It. The target lift is 1.54 MM at top dead center and 1.6 mm for slightly more power. So as you can see less than a tenth of a millimeter of lift at top dead center can mean the difference between spot on an advanced
Too far advanced would cause a knocking sound the same to the pre detonation knocking sound that you have
Yeah, this makes sense.
The valves were all pretty good, except for one a bit loose. They all were within .203 and .254mm. I tried to make sure they felt the same with the .203mm feeler, just slightly tight. But I have no idea if that is right, really. It's hard to feel the right tightness from YouTube...
It was timed 4k miles ago in the local shop, before I ever drove it. But I suppose the new belt could have jumped.
I can't tell if this is related, but the metallic pinging sound that I heard last summer might be the same as the knock I'm hearing now. I have spent a long time trying to listen to different parts of the engine. It's easy to hear once you notice it, and it seems to be coming from the front of the engine. On close inspection, the only place I can hear it is from the thermostat housing...??? The head just behind that is one of the quietest places on the whole engine, but when you listen to the thermostat housing you get a loud and distinct bell ringing coming and going.
It's frustrating because I have no clue if it really is running well or not. I have very few real life reference points.
I'm at the end of my abilities on this, so I'll have to try to drop it at the shop. Thanks for the help.
By the way, the valve stems look good from the side. But I was unable to get any out to really inspect them. The arms don't come up far enough, even when lose and at full closed position. I'd probably have to release the whole rack of them and pull them completely off the stems to get at the caps.
The valves were all pretty good, except for one a bit loose. They all were within .203 and .254mm. I tried to make sure they felt the same with the .203mm feeler, just slightly tight. But I have no idea if that is right, really. It's hard to feel the right tightness from YouTube...
It was timed 4k miles ago in the local shop, before I ever drove it. But I suppose the new belt could have jumped.
I can't tell if this is related, but the metallic pinging sound that I heard last summer might be the same as the knock I'm hearing now. I have spent a long time trying to listen to different parts of the engine. It's easy to hear once you notice it, and it seems to be coming from the front of the engine. On close inspection, the only place I can hear it is from the thermostat housing...??? The head just behind that is one of the quietest places on the whole engine, but when you listen to the thermostat housing you get a loud and distinct bell ringing coming and going.
It's frustrating because I have no clue if it really is running well or not. I have very few real life reference points.
I'm at the end of my abilities on this, so I'll have to try to drop it at the shop. Thanks for the help.
By the way, the valve stems look good from the side. But I was unable to get any out to really inspect them. The arms don't come up far enough, even when lose and at full closed position. I'd probably have to release the whole rack of them and pull them completely off the stems to get at the caps.
...interesting....
I cheated a bit, and let it idle for almost 10 minutes this morning before driving. But it seemed to me to be smoother, and more 'tuned' on the drive in this morning. I'll drive it without warming up this afternoon, and see if my impression is the same.
I'm suspicious of why my performance and MPG is so different than others, and these noises and rattles are all I have to go on!
I cheated a bit, and let it idle for almost 10 minutes this morning before driving. But it seemed to me to be smoother, and more 'tuned' on the drive in this morning. I'll drive it without warming up this afternoon, and see if my impression is the same.
I'm suspicious of why my performance and MPG is so different than others, and these noises and rattles are all I have to go on!
lmwong
Member
I have a 200 TDI but I think I have the same problem!? https://www.youtube.com/watch?v=zw1ib4EFPSg
I took it to a mechanic and they said the vacuum pump needed replacing. They did that and the noise went away, but she was now down on power with lots of white exhaust and told me the engine needed rebuilding for the cost of an arm and a leg. I took it home and advanced the timing which did the trick for a few days but the tapping noise came back (not a knock but a distinct tap)! Hopefully it just needs a valve adjustment.
What would cause valves to go out of alignment and need adjusting?
I took it to a mechanic and they said the vacuum pump needed replacing. They did that and the noise went away, but she was now down on power with lots of white exhaust and told me the engine needed rebuilding for the cost of an arm and a leg. I took it home and advanced the timing which did the trick for a few days but the tapping noise came back (not a knock but a distinct tap)! Hopefully it just needs a valve adjustment.
What would cause valves to go out of alignment and need adjusting?